This invention relates to a lubricating oil metering control system for a rotary engine, and more particularly for lubricating the apex seals of a turbocharged, stratified charge rotary engine with an unthrottled intake.
Various systems for controlling lube oil flow to a rotary engine as a function of engine load and speed have been proposed.
One system is described in U.S. Pat. No.4,765,291 wherein an oil metering pump rate responds to the movement of a diaphragm which is exposed to exhaust gas pressure. However, in such a system various parts would have to be made to withstand the high exhaust temperatures. Futhermore, exhaust gas pressure can vary depending on type and condition of the muffler and exhaust system, and upon whether or not there are leaks in the exhaust system. This leads to the unreliability of a lube oil metering system wherein lube oil is metered as a function of exhaust pressure.
Other systems such as described in U.S. Pat. Nos. 3,788,782, 3,827,836 and 3,834,843 control lube flow rate as a function of at least engine speed and throttle opening. Such schemes will not function in an unthrottled, fuel injected stratified charge rotary engine since there is no throttle. Accordingly, a load dependent lube oil metering system is desired for an unthrottled, stratified charge rotary engine wherein lube oil flow is not dependent upon exhaust gas pressure or subject to high exhaust temperatures.